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4.0 Supercharged


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hey thanks evryone for helpin me out with questions before great replies. so I'm rebuilding a 6 cyl 4.0 for my comanche. now i would really like to put an eaton m90 supercharger on it. from what i hear it should be rather painless. does anyone have info or concerns on this? also if i do this should i put it on during the "break in" period of my new rebuild or wait till its broken in to install? thanks everyone

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Putting it on during the break in period will only help make rebuild issues become apparent much faster. I am purposely waiting until I have put 500 miles on my rebuilt engine since if any small issues come up they will less likely to become major issues due to supercharging.

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Putting it on during the break in period will only help make rebuild issues become apparent much faster. I am purposely waiting until I have put 500 miles on my rebuilt engine since if any small issues come up they will less likely to become major issues due to supercharging.

 

Can you explain in a little greater detail why?  I actually do know exactly why one would choose to wait, but i am having a major brain fart and can't seem to make my thoughts into words and need to hear it explained. :dunce:

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This is from a craigslist ad that I emailed myself for reference  he had the kit listed for 1200 installed:   

 

 

Jeep 4.0L Supercharger kit and installation

Date: 2013-03-23, 12:52PM


Complete kit including installation to supercharge 90-98 Jeep wrangler, Cherokee and Grand Cherokee OBDI and early OBDII 4.0L engines. This kit works best for pre '99 engines as the mapping system can be fooled easily by replacing the stock 19# injectors with 30# injectors for the increased fuel required for the 5-6 pounds of boost this system produces. Fits completely underhood on wrangler and grand's but some trimming of hood undersupport and small bubble or cheasy plastic hood scoop is required for the Cherokees. Extensively tested and found to be a reliable increase in horsepower though does come with a few drawbacks - (1) you will loose your Air conditioning system and cruise control as the charger fits in place of the old AC unit. (2) replacing spark plugs in the future will become time consuming as the charger covers 4 of them. (3) Increased tread wear of the tires.

Like Jack in the Box - these kits are made to order.
Currently I do have one complete kit in stock.
Included in the sale of basic kit (non intercooled) :

- Reconditioned Eaton M90 (Ford Thunderbird) Supercharger
- SC mounting plate (stock AC mount utilized)
- Rear throttle body inlet pipe and cone filter
- Intake manifold pressure piping (non intercooled)
- NGK spark plugs, cap, rotor, and plug wires for a full ignition tune up.
- remanned 30# fuel injectors
- proper length serpentine belt
- full installation and tuning for a turn key upgrade.

For the DIY 'ers I will sell the mounting kit and/or the pieces individually. 

Call David at 541-206-7717 with your ?'s and to schedule an installation appointment.

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ftpiercecracker1, on 02 May 2013 - 00:16, said:

 

 

Alexia, on 02 May 2013 - 00:04, said:

Putting it on during the break in period will only help make rebuild issues become apparent much faster. I am purposely waiting until I have put 500 miles on my rebuilt engine since if any small issues come up they will less likely to become major issues due to supercharging.

Can you explain in a little greater detail why? I actually do know exactly why one would choose to wait, but i am having a major brain fart and can't seem to make my thoughts into words and need to hear it explained. :dunce:

 

Imagine a lightly frozen over lake. Set a ten pound weight on it to test how much it can hold. The ice will be seen and heard cracking slowly form as the ten pound weight stresses the ice. Before the cracks get worse the weight can be removed quickly saving it and thus preventing the cracks from becoming broken ice.

The next time a one hundred pound weight is put on the ice. The ice breaks and the weight sinks to the bottom. Now the weight is gone and the ice is very broken.

 

In both scenarios the ice was defective for holding weight, but in one of them the damage was minimized since it was possible to detect the damage earlier thus stopping before it became catastrophic. It is the same idea for an engine. If a defective part was used or it was rebuilt improperly it will fail. It is a just a matter of how fast and how catastrophic.

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I like your analogy. :thumbsup:

 

But can't a poorly rebuilt engine run perfectly fine for many thousands of miles? How would you know when and if a rebuilt engine would be"ready" for the next step? Like a super, turbo, or NOS.  Even if you rebuild an engine and it is dead nuts perfect to spec, at no point in its life will it be able to support any of the pre mentioned performance boosters, at least for any length of time.

 

I know i am REALLY belaboring this. ;)  but i just really like talking performance stuff.    Either way i think the best path is what has already been said. Your first step is to rebuild your engine. During which you upgrade the appropriate internals so that if the basic rebuild passes muster, lets say 500 miles :dunno:,   it will be safe to add the supercharger.

 

 

I can't wait to see the finished product.  :D

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I like your analogy. :thumbsup:

 

But can't a poorly rebuilt engine run perfectly fine for many thousands of miles? How would you know when and if a rebuilt engine would be"ready" for the next step? Like a super, turbo, or NOS.  Even if you rebuild an engine and it is dead nuts perfect to spec, at no point in its life will it be able to support any of the pre mentioned performance boosters, at least for any length of time.

 

I know i am REALLY belaboring this. ;)  but i just really like talking performance stuff.    Either way i think the best path is what has already been said. Your first step is to rebuild your engine. During which you upgrade the appropriate internals so that if the basic rebuild passes muster, lets say 500 miles :dunno:,   it will be safe to add the supercharger.

 

 

I can't wait to see the finished product.  :D

The main reason I would not want to toss a supercharger on a freshly rebuilt 4.0L or even a stroked 4.0L is that neither were ever tuned from the factory to handle a supercharger or turbocharger. With each setup being different and no known factory default for that kind of setup I certainly would not want to be trying to tune an engine during the break in period.
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